81985510552 has 72 divisors (see below), whose sum is σ = 169715923020. Its totient is φ = 36822947200.

The previous prime is 81985510531. The next prime is 81985510561. The reversal of 81985510552 is 25501558918.

It is a junction number, because it is equal to n+sod(n) for n = 81985510496 and 81985510505.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 351869028 + ... + 351869260.

Almost surely, 2^81985510552 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81985510552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84857961510).

81985510552 is an abundant number, since it is smaller than the sum of its proper divisors (87730412468).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81985510552 is a wasteful number, since it uses less digits than its factorization.

81985510552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 745 (or 377 counting only the distinct ones).

The product of its (nonzero) digits is 720000, while the sum is 49.

The spelling of 81985510552 in words is "eighty-one billion, nine hundred eighty-five million, five hundred ten thousand, five hundred fifty-two".